#!/usr/local/bin/perl

use strict;
use warnings;

our %word_hash;

# used to determine which word should be listed first.
sub word_hash_compare 
{
    #print "$a --- $b\n";

    # If words $a and $b have the same frequency, then the
    # work that comes first in the alphabet is "smaller".
    if ($word_hash{$a} == $word_hash{$b}) {

        # $a cmp $b returns -1 if $a < $b, 1 if $b > $a, and 0 if they are equal..
	return $a cmp $b;  
    }

    # if words $a and $b have different frequencies, then the 
    # larger frequency should come first.
    
    # the perl operator $x <=> $y returns -1 if $x < y, 1 if $y < $x, and 0 if they are equal
    return $word_hash{$b} <=> $word_hash{$a};
}

#
# main
#

# process each line on the standard input.
while(my $line = <>) {

    # for each word in the line.
    foreach my $word (split(/\s+/, $line)) {
	
	# conver to all lower-case
	my $lc_word = lc($word);
	$word_hash{$lc_word}++;
    } # end for
} # end while

foreach (sort word_hash_compare  keys %word_hash) {
    print "$word_hash{$_}\t$_\n";
}